1. Field of the Invention
The present invention is directed to a railborne mobile crane with a superstructure which is arranged so as to be swivelable about a vertical axis together with a counterweight and a boom on a truck. The contours of the superstructure are arranged within a prescribed clearance gauge of a section of track. The superstructure is outfitted with a device for compensation of curve superelevations.
2. Description of the Related Art
A railborne mobile crane mounted on a truck with a superstructure arranged so as to be swivelable about a vertical axis together with a boom and a counterweight is used for working on a track and adjacent to the track. The usefulness of such a railborne mobile crane depends extensively upon construction of the crane, the boom and the counterweight. Particularly when working on lengths of track in which the track is laid parallel to an adjacent track or is within a tunnel, special steps have to be taken to maintain a necessary clearance gauge with respect to the adjacent track or tunnel wall.
When working on two-track or multi-track stretches, it must be ensured that under all circumstances, for reasons of safety, no parts of the crane that jut out, such as parts of the counterweight, swivel into the prescribed clearance gauge of the adjacent track. Various crane constructions are known in which contours of the superstructure remain, during the use of the crane, within the prescribed clearance gauge of the track section.
A dangerous situation arises however when the crane contours conform to the prescribed clearance gauge but, because of superelevation of the track along curves, a railborne vehicle traveling on the adjacent track is inclined toward one side, and therefore enters the clearance gauge area of the railroad mobile crane.
During use, the railroad crane is usually oriented to the horizontal for purposes of maintaining stability and a preferred center of gravity. A curve superelevation compensation device is provided for horizontally orienting the crane on a superelevated i.e. curved or canted, section of track. The compensation device pivots the superstructure with the boom and the counterweight relative to the truck of the crane until the swiveling axis of the crane extends vertically. However, as a result of this righting of the crane relative to the length of track, the contour of the superstructure is shifted into the prescribed clearance gauge of the adjacent track so that a collision will occur with a railborne vehicle traveling on the adjacent track.